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Keywords:

  • chemoselectivity;
  • diols;
  • ketones;
  • organotin catalysts;
  • oxidation

Abstract

Thumbnail image of graphical abstract

Get selective! A selective oxidation of 1,2-diols to α-hydroxyketones catalyzed by organotin compounds has been developed (see scheme). Invaluable chemo- and stereoselectivity were found in the reaction. The catalytic system has been achieved by electrochemical and chemical oxidation.

Electrochemical oxidation of 1,2-diols with a catalytic amount of an organotin compound and a bromide ion as mediators has been developed. Various cyclic and acyclic 1,2-diols were oxidized into the corresponding α-hydroxyketones in good to excellent yields without C[BOND]C bond cleavage. Also, oxidation with the use of chemical oxidants was accomplished in the presence of a catalytic amount of an organotin compound. These reactions could discriminate 1,2-diols from isolated hydoxyl groups or 1,3-diols. In the case of a conformationally restricted cyclic 1,2-diol, the axial hydroxyl group was oxidized exclusively. Mono-, di-, and trialkylated tin compounds were examined as mediators and dialkylated tin compounds showed higher catalytic activity than mono- and trisubstituted ones. Me2SnCl2 was found to be the most suitable mediator for the selective oxidation.